c# - streamReader.ReadToEndAsync() 改变消息内容

问题描述

我有一个 .Net Core 3.1 Web API 需要与外部服务交互，该服务提供来自 WCF 服务的多部分/相关响应，上下文中的附件如下所示。

HTTP/1.1 200 OK
Cache-Control: private
Content-Length: 1790633
Content-Type: multipart/related; type="text/xml"; start="<8fb5b3efa6474add9032cb80870dc065>"; boundary="------=_Part_20200731120159.494997"
Server: Microsoft-IIS/10.0
Set-Cookie: ASP.NET_SessionId=jga2opbhoirgnhjhmmsuxi1k; path=/; HttpOnly; SameSite=Lax
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Set-Cookie: ARRAffinity=f7b4f7f5d8cbd8c8bc5d9a4bf49e8b5938412c4294f6e2c2b5c2d5cfc4b4d437;Path=/;HttpOnly;Domain=lparouterpoc.azurewebsites.net
Date: Fri, 31 Jul 2020 13:33:04 GMT


--------=_Part_20200731120159.494997
Content-Type: text/xml; charset=UTF-8
Content-Transfer-Encoding: binary
Content-Id: <8fb5b3efa6474add9032cb80870dc065>

<?xml version="1.0" encoding="iso-8859-1"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
...
</SOAP-ENV:Envelope>
--------=_Part_20200731120159.494997
Content-Type: application/octet-stream
Content-Transfer-Encoding: binary
Content-Id: 7b1fff220df5@xxxxx

%PDF-1.5
%����
...
Additional characters added in here
...
%%EOF

--------=_Part_20200731120159.494997
Content-Type: application/octet-stream
Content-Transfer-Encoding: binary
Content-Id: 844eb478dc05@xxxxx

%PDF-1.5
...
Additional characters added here
...
%%EOF
--------=_Part_20200731120159.494997--

使用 SOAP UI，我看到有附件，但每个附件都是空白 PDF。

.Net Core API 中的代码是

using (var response = await Client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead))
{
    var stream = await response.Content.ReadAsStreamAsync();
    using var streamReader = new StreamReader(stream, Encoding.UTF8);
    var message = await streamReader.ReadToEndAsync(); // This is where output is changed to add additional characters
    var headers = response.Headers;
    return new customResponse
    {
        ContentResult = new ContentResult
        {
            Content = message,
            ContentType = response.Content.Headers.ContentType?.ToString(),
            StatusCode = (int)response.StatusCode
        },
        ResponseHeaders = headers
    };
}

下图显示了附加字符进入导致 PDF 无效\损坏\空白的示例。

另一个特点是内容长度从 1021690 到 1790633。

到目前为止，我已经能够对其进行调试并在文件进入消息（字符串）之前测试它们是否正确，因为我能够读取多部分内容并将文件写入磁盘时检查文件确实正确使用

var content = await response.Content.ReadAsMultipartAsync();
for (var i = 0; i < content.Contents.Count; i++)
{
    var item = content.Contents[i];
    if (item.Headers.ContentType.ToString() == "application/octet-stream")
    {
        var bytes = await item.ReadAsByteArrayAsync();
        File.WriteAllBytes(@$"c:\temp\{i}.pdf", bytes);
    }

}

然后遍历content.Contents.

如果有人能告诉我为什么会发生这种情况以及如何阻止这种情况发生，我将不胜感激

进一步的调查和假设是否可以归结为编码？附件的 WCF 服务是 TransferEncoding = "binary"

图像的左侧和中间是相同的，从我的 API 直接写入磁盘的中间（不是我需要的）显示文件可以读写。

右边是服务的直接输出，返回到 SOAP UI 并按预期下载。

在监视窗口中查看响应时，传输编码为空，因此对如何解决此问题感到有些困惑。

标签： c#.netdotnet-httpclientmultiparthttpresponsemessage

尝试这个，

public async Task<HttpResponseMessage> Post(string requestBody, string action)
{
    using (var request = new HttpRequestMessage(HttpMethod.Post, ""))
    {
        request.Headers.Add("SOAPAction", action);
        request.Content = new StringContent(requestBody, Encoding.UTF8, "text/xml");
        var response = await Client.SendAsync(request);
        return response;
    }
}

然后在你的控制器中像这样返回它

var result = await _service.Post(requestBody, action);

var stream = await result.Content.ReadAsStreamAsync();
await stream.CopyToAsync(HttpContext.Response.Body);

c# - streamReader.ReadToEndAsync() 改变消息内容

问题描述

解决方案

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